Alarmed by plunging television ratings for the Academy Awards, the organization behind the Oscars has announced that it is adding a category for blockbuster films and shortening the telecast by giving out some awards during commercial breaks.

Yet, adding a category for “outstanding achievement in popular film,” as John Bailey, the president of the Academy of Motion Picture Arts and Sciences, put it in a letter sent to members this week, could create new problems for the beleaguered organization.

What if a movie many see as a legitimate best picture contender — the worldwide smash “Black Panther,” for instance — receives a nomination for the populist Oscar but not for best overall picture? Does that mean “Black Panther” and films like it are second-class citizens?

The letter, co-signed by Dawn Hudson, the academy’s chief executive, did not say what would constitute a “popular” film or whether movies nominated in that category could also be nominated for best picture. (An academy spokeswoman later said that they could.) The category will make its debut at the next Oscars ceremony, which will be held on Feb. 24.

“Eligibility requirements and other key details will be forthcoming,” the letter said.

The academy’s board also voted to keep the telecast to three hours, which it described as an effort to deliver “a more accessible Oscars for our viewers worldwide.” To trim the telecast — the last show, in March, stretched nearly four hours — the academy said it would present “select categories” during commercial breaks, with the winning moments edited and aired later during the broadcast.

The TV producers overseeing the annual telecast have long pressed the academy to reduce the number of awards presented on air. (There are now 25.) The academy did not say which categories could be edged aside. The most likely are the Oscars presented for short films.

A third change will not take effect until 2020. The telecast will be held earlier in the year — most likely early February, although the academy will have to work around the Super Bowl schedule — in an attempt to speed up Hollywood’s awards season.

The addition of a category for blockbusters was immediately assailed by some prominent film critics.

Manohla Dargis of the New York Times called the changes “stupid, insulting and pathetically desperate” on Twitter. “Five Came Back” author Mark Harris tweeted that the popular film award “is a ghetto and will be perceived that way.” But even many of those disparaging the new category allowed that the academy had to take some kind of action.

Viewership of the Oscar telecast is plummeting. A record low of 26.5 million people watched this year’s telecast, nearly a 20 percent drop from a year earlier. As recently as four years ago, the Academy Awards had an audience of 43.7 million viewers.

“We have heard from many of you about improvements needed to keep the Oscars and our academy relevant in a changing world,” Bailey wrote. “The Board of Governors took this charge seriously.”

The Oscar telecast is a big business, generating 83 percent of the academy’s $148 million in annual revenue. ABC controls broadcast rights for the show until 2028 at a cost of roughly $75 million a year. ABC was seeking as much as $2.8 million per 30-second commercial for the most recent telecast.

Reasons for the Oscars’ decline abound — the general fragmentation of the media landscape is one — but the central complaints have been about the telecast’s marathon length and increasing tendency to honor niche films that the majority of American moviegoers have not seen. Last year’s best picture winner, “The Shape of Water,” had sold about $60 million in tickets at the time after playing in theaters for 14 weeks.

“Black Panther,” by comparison, took in $202 million over its first three days.

In 2009, the academy tried to make room for more widely seen films by doubling the number of potential nominees for the best picture award to 10 from five.

That shift occurred after “The Dark Knight,” a critically acclaimed superhero film, was shut out of the best picture category, despite receiving nominations in eight others and winning in two.

But allowing more best picture nominations did little to solve the problem. For the most part, moviedom’s elite continued to bypass films with large audiences and simply put forward additional niche ones.